Reversible engine mount

ABSTRACT

A two-cycle gasoline engine having a cylinder block mountable in several alternative positions about its axis so as to allow variable orientations of its exhaust.

[ 1 Oct. 3, 1972 United States Patent Cookson 3,353,525 Nutten et al. 123/73 R X [541 REVERSIBLE ENGINE MOUNT [72] Inventor:

Cecil T. Cookson, 918 Cornell Drive, Burbank, Calif. 91504 Pnmwy Examiner-Wendell Burns Aug. 31, 1970 Attorney--Fowler, Knobbe & Martens [22] Filed:

ABSTRACT A two-cycle gasoline engine having a cylinder block mountable in several alternative positions about its 21 Appl. No.: 68,349

[52] US. Cl.............l23/73 A, 123/73 R, 123/193 C, I 123/D1G. 1, l23/D1G. 6, l23/D1G. 7 [51] Int.

Fozb 33/04 axis so as to allow variable orientations of its exhaust. D16. 6, DIG. 7,

[58] Field of Search.......l23/D1G. 1,

123/193 C, 73 R, 73 A 4 Claims, 9 Drawing Figures References Cited UNITED STATES PATENTS 1,480,745 Cutshall..,.......'........123/193 C PATENTEDMB M I 3. 95.240

sum 3 or 4 INVENTOR. 656/4 7." COO/(50W BY FOWL 5 18/1/0555 (3 MQQTEA/ REVERSIBLE ENGINE MOUNT Small two-cycle gasoline engines having a power output of the order of one or two horsepowers can be used to drive many different types of machines, such as pumps, hand-held chain saws and minibikes. Usually, although not necessarily, the engine is oriented on its side, or slightly inclined from the horizontal, with its carburetor extending upward for convenience in making fuel mixture adjustments. Exhaust gases leave the engine through an exhaust port which extends through the wall of its cylinder. Depending upon the type of apparatus with which the engine is being used, it may be desirable to lead the exhaust gases away, above, below, or along the side of the engine. For example, in the case of a minibike, the exhaust pipe should extend preferably below the engine, away from the rider. If, on the other hand, the engine is used with a pump, the exhaust pipe should extend upward, to prevent scorching the surface upon which the pump rests. And, if the engine is used on a hand-held chain saw, the preferred direction for the passage of exhaust gases will be sideways.

If the location of the exhaust relative to the location of the carburetor is fixed and the carburetor is to extend upward, the designer of the equipment which is to be driven by the engine must lead his exhaust pipe to wherever the engine exhaust port happensto be. In accordance with the present invention, a gasoline engine is made more versatile by permitting the relative location of its carburetor and its exhaust port to be changed depending upon the desired application of the engine. In carrying out the invention, the engine block through which the exhaust port extends and the crankcase upon which the carburetor is mounted are so configured as to permit the engine block to be mounted on the crank- -case in several alternative positions, thereby permitting several different orientations of the exhaust port relative to the carburetor.

In accordance with a more specific feature of the invention, provisions are made to allow the combustible mixture which is fed from the carburetor into the crankcase to flow unimpeded from the crankcase into transfer passages in the wall of the cylinder unobstructed, regardless of the position in which the block is mounted upon the crankcase. In particular, positioning elements extend from the bottom of the cylinder block and from the edge of an opening in the crankcase upon which the block is seated. These positioning elements serve to determine the lateral position of the cylinder block upon the crankcase and, in accordance with the invention, are in registry in all alternative positions of the block upon the crankcase. Moreover, regardless of the position of the block upon the crankcase, none of the positioning elements which extend from the crankcase obstruct the entry of the combustible mixture from the crankcase into the transfer passages which are in the side of the cylinder.

The present invention and its advantages will be more clearly understood with reference to the follow ing description of a preferred embodiment thereof taken in conjunction with the accompanying drawings wherein:

FIG. 1 is a simplified exploded perspective view of a two-cycle gasoline engine incorporating the present invention;

FIG. 2 is a cross section through the engine illustrated in FIG. 1, shown mounted upon a starter housing;

FIG. 3 is a perspective view of the cylinder block, partially cut away to show the transfer passages in the wall of the block;

FIGS. 4a, b, and c are cross sections taken along line 4-4 of FIG. 2 illustrating the manner in which the positioning bosses which extend inwardly from the crankcase, clear the transfer passages in the wall of the cylinder block in each of three alternative positions of the cylinder block upon the crankcase; and

FIGS. 5a, b and c illustrate the manner in which the engine incorporating the present invention might be mounted on three different machines, with the exhaust port of the engine being oriented differently relative to the carburetor in each of the three engine applications.

An exemplary two-cycle gasoline engine 11 incorporating the present invention is illustrated in FIGS. 1-3. Only its principal components are shown, these including a crankcase 13, a cylinder block 15 having walls defining a cylinder 17 therein, and a piston 19 adapted to move within the cylinder. Power is transferred from the piston 19 through a connecting rod 21 to a crankshaft assembly 23 which is mounted for rotation within the crankcase by a pair of bearings (not shown). The crankshaft assembly 23, which may be of the type more completely described in US. Pat. No. 3,147,638 issued to H. T. M. Rice on Sept. 8, 1964, includes a pair of crank disks 25 and 27 connected by a crank pin 29 with individual crankshaft sections 31 and 33 extending in opposite directions from respective ones of the crank disks to be supported by the respective bearings. The connecting rod 21 is coupled at one end to the piston 19 by a pin 22 and at the other end to the crank pin 29 by means of a clamp 35 and a pair of bolts 37, bearings being provided at both ends of the crankshaft to reduce friction.

When the engine is operating, the crankshaft assembly 23 is turned by the piston 19 through the connecting rod 21 and power is usually taken from the end of the crankshaft section 31, while a flywheel is usually mounted at'the end of the other crankshaft section 33.

To produce the combustible mixture of gasoline and air a carburetor 43 is mounted on the side of the crankcase 13 upon a flange 45. An opening 47 is provided through the flange 45 and through the side of the crankcase 13 to allow passage of the combustible mixture from the carburetor to the inside of the crankcase. Once inside the crankcase, the combustible mixture is spun around and is propelled upward toward an opening 49 which is also through the side of the crankcase but which with reference to FIGS. 1 and 2, will be referred to as being through the top of the crankcase. Surrounding the opening 49 is a square mounting flange 51 adapted to receive a similar mounting flange 53 on the bottom of the cylinder block 15. When the cylinder block is mounted on the crankcase 13 the cylinder block flange 53 is securely bolted to the crankcase flange 51 so that the two flanges are juxtaposed as seen in FIG. 2. For better sealing, a gasket 54 is normally provided between them. The means whereby the cylinder block is bolted onto the crankcase 13 is shown as a set of four bolts 56 anchored upon the crankcase flange 51 and .a corresponding set of four openings 58 which extend through the cylinder block flange 53 in registry with the bolts 56. A set of four nuts (not shown) are threaded on top of the bolts 56 once the block has been seated upon the crankcase 13 to complete the mounting process.

To permit the combustible mixture to pass from the crankcase 13 through its opening 49 into the combustion chamber 52 between the top of the piston 19 and the top of the cylinder 17, two sets of transfer passages 55 and 57 are provided in the walls of the cylinder. The transfer passages 55 and 57 are spaced apart on opposite sides of a pair of exhaust ports 59 which also extend through the walls of the cylinder. In the illustrated embodiment, the passages 55 and 57 are in the shape of grooves which run axially along the side wall of the cylinder 17 from the cylinder block flange 53 toward the opposite end 60 of the cylinder sufficiently far to establish communication between the combustion chamber 52 and the interior of the crankcase 13 when the piston 19 is close to its bottom dead center. The grooves, or passages, 55 and 57 are recessed in the cylinder block 15 to a depth defined by a circle 49a which is concentric with the cylinder 17 and which is substantially of the same size as the circular opening 49 in the crankcase 13. Through an opening 71 a spark plug 72 is screwed into the top of the cylinder.

In operation, the combustible mixture is scavenged by the rotating crank disks 25 and 27 from the carburetor through the crankcase l3 and through the transfer passages 55 and 57 into the combustion chamber 52. There it is ignited by the spark plug 72, propels the piston 19 toward the crankcase l3, and exits through the exhaust ports 59.

As mentioned previously, it is an important feature of the present invention that the engine may be assembled in several different ways, in each of which its exhaust ports 59 point in a different direction relative to the crankcase l3, and in particular relative to the carburetor 43. This is achieved partly by positioning the mounting bolts 56 and the mounting apertures 58 in the respective flanges 51 an 53 symmetrically, thereby to permit the cylinder block 15 to be mounted in several different orientations about the axis 75 of the cylinder 17. Yet the engine components are so configured that the transfer passages 55 and 57 are operative to carry the combustible mixture from the crankcase 13 to the combustion chamber 52 in each of several positions of the cylinder block 15 relative to the crankcase 13.

In particular, certain positioning means which are provided at the interface of the cylinder block 15 and the crankcase 13 to determine the lateral position of the cylinder block upon the crankcase are so placed that they permit free passage of the combustible mixture through the passages 55 and 57, regardless of the position of the cylinder block upon the crankcase.- As best seen in FIG. 1, a pair of arcuate positioning lips 63 and 65 extend from the bottom of the cylinder 17 between the transfer passages 55 and 57. As seen in FIG. 2, the positioning lips 63 and 65 extend into the crankcase opening 49 facing one another from opposite sides of the cylinder 17 from between the passages 55 and 57. Extending radially inwardly from the walls of the crankcase opening 49 toward the positioning lips 63 and 65 are a set of positioning bosses 69a-69 which together with the positioning lips 63 and 65 serve to limit, and thereby define, the lateral movement of the block 15 upon the crankcase 13. The positioning bosses 69a-69d are so distributed around the periphery of the opening 49 that all of them register with the positioning lips 63 and 65 and none of them project into one of the groove-like passages 55 and 57 regardless of the alternative position in which the cylinder block 15 is mounted upon the crankcase 13.

FIG. 4a shows how the positioning bosses may be distributed in accordance with the invention. The figure also shows the distribution of the transfer passages 55 and 57 relative to the bosses 69 when the cylinder block 15 is so mounted that its exhaust ports are oriented clockwise from the carburetor when viewed from above. FIGS. 4b and 40 show the location of the transfer passages 55 and 57 when the block 15 is mounted in its second and third positions respectively, in which the exhaust ports 59 are directed opposite to and in line with the carburetor 43. As' clearly seen in FIGS. 4a-4c, the transfer passages 55 and 57 are clear of the positioning bosses 69a-69d in all three of the i] lustrated positions of the cylinder block 15. With the exemplary embodiment shown herein, no attempt was made to enable the engine to operate with the fourth possible engine mounting arrangement in which the exhaust ports 59 would be directed at 270 clockwise relative to the carburetor. This is so because in practice the exemplary engine always has a starter housing attached to its side into which housing the crankshaft section 33 extends. Had a provision been made to have the exhaust ports 59 extend in this additional direction, it would have been useless since there would have been no room between the cylinder block 15 and the housing to lead the exhaust gases away.

The crank disks 25 and 27 rotate in a plane indicated by the axis 77 in FIG. 4a and project slightly above the bottom edges of the positioning lips 63 and 65. This presents no problem when the cylinder block 15 is in the position shown in FIG. 4a, since there is a clearance for them between the positioning lips 63 and 65. In order to provide a similar clearance when the block 15 is in its position shown in FIGS. 4b and 4c, the positioning lips are notched substantially at their centers, as shown at 67.

FIGS. 5a, 5b, and 50 show the three applications of the engine corresponding to the three orientations of the cylinder block illustrated in FIGS. 4a, 4b, and 40 respectively. Thus, when the exhaust ports 59 are at 90 with the carburetor mounting flange 45, the engine is adapted to be mounted upona hand-held chain saw 77 so as to extend parallel to its blade with the carburetor 43 pointing up and the exhaust ports 59 directed sideways, as shown in FIG. 50. When, on the other hand, the exhaust ports 59 and the carburetor mounting flange 45 are diametrically opposite, as in FIG. 4b, the engine is suitable for mounting on a minibike 79 with the carburetor still directed upward, but the exhaust ports 59 now being directed directly downward as seen in FIG. 5b. Finally, the configuration shown in FIG. 40, wherein the exhaust ports 59 and the carburetor mounting flange 45 are directed in the same direction, is shown to be of the one most suitable when the engine is used with a pump 81 on which both the carburetor 43 and the exhaust ports 59 are directed upwardly.

From the above it is apparent that there has been disclosed a techniquefor making a single engine adaptable to several applications by the expedient of so building the engine as to allow it to be assembled in several different configurations, each of which is particularly adapted to a different application. Yet this is achieved without a significant increase in the cost of manufacturing the engine and with no adverse effects upon engine operation.

What is claimed is:

1. In a two-cycle gasoline engine the combination comprising:

a. a crankcase having an intake port for receiving a combustible mixture and a side wall portion terminating in a mounting flange and having a circular opening centered in said flange;

b. a block having walls defining a cylinder with an exhaust port through its side, said block terminating in a mounting flange at its bottom; 7

c. passages open to said cylinder, running axially in the wall of said block from said flange;

d. positioning means, integral with said block, ex-

tending axially from said flange and around said cylinder between said passages;

e. means for mounting said block upon said crankcase in alternative positions about the axis of said cylinder in each of which their flanges are juxtaposed and said positioning means extend into said crankcase opening; and

f. second positioning means integral with said crankcase and extending inwardly from the walls of said opening toward said first positioning means, said second positioning means being spaced to register with said first positioning means and to clear said passages in all positions of said block so as to permit combustible gases to pass into said passages from said crankcase unobstructed by said second positioning means.

2. A combination in accordance with claim 1 and characterized further in that:

a. there are two sets of passages in the wall of said block, said sets being spaced apart on opposite sides of said exhaust port; and

b. said first positioning means is comprised of two symmetrical arcuate portions facing each other from between said sets of passages, both said portions being notched substantially at their centers to provide clearance for a crank rotating within said crankcase when the said block is in two of its alternative positions.

3. ln a two-cycle gasoline engine the combination comprising:

a. a crankcase having an intake port for receiving a combustible mixture and a circular opening surrounded by a flange;

b. a cylinder block having walls defining a cylindrical chamber open at one end to admit a piston and g c. a pair of arcuate positioning lips extending from the open end of said cylinder between said grooves;

. means for mounting said cylinder block upon said crankcase in any of several alternative positions in each of which said mounting flanges are juxtaposed and said'positioning lips extend into the opening in said crankcase flange; and

. a set of centering bosses extending radially inwardly from the walls of said crankcase opening toward said positioning lips, said bosses being so distributed that all of them register with said positioning lips and none of them extend opposite one of said grooves regardless of the alternative position in which said cylinder block is mounted upon said crankcase, whereby said combustible mixture can flow unobstructed from said crankcase and through said grooves to the said opposite end of said cylinder regardless of the particular position in which said cylinder block is mounted.

4. In a two-cycle gasoline engine the combination comprising:

a. a crankcase having an opening and an intake port in its side;

b. a carburetor mounted upon said crankcase at said intake port;

0. a block having walls defining a cylinder with an exhaust port through its side;

(1. means for mounting said block upon said crankcase at said opening in alternative positions about the axis of said cylinder, thereby to permit different orientations of said exhaust port relative to said carburetor;

. a piston within the cylinder defining a combustion chamber with the end of the cylinder remote from the crankcase;

. means defining passages in the wall of said block open to said cylinder and open to the interior of the crankcase for permitting the combustible mixture to flow into the combustion chamber; and

g. means on said block and said crankcase for laterally positioning the cylinder with respect to said crankcase opening, said positioning means being arranged to clear the passages in all positions of the block so as to permit the combustible mixture to pass through the passages from the crankcase unobstructed by the positioning means. 

1. In a two-cycle gasoline engine the combination comprising: a. a crankcase having an intake port for receiving a combustible mixture and a side wall portion terminating in a mounting flange and having a circular opening centered in said flange; b. a block having walls defining a cylinder with an exhaust port through its side, said block terminating in a mounting flange at its bottom; c. passages open to said cylinder, running axially in the wall of said block from said flange; d. positioning means, integral with said block, extending axially from said flange and around said cylinder between said passages; e. means for mounting said block upon said crankcase in alternative positions about the axis of said cylinder in each of which their flanges are juxtaposed and said positioning means extend into said crankcase opening; and f. second positioning means integral with said crankcase and extending inwardly from the walls of said opening toward said first positioning means, said second positioning means being spaced to register with said first positioning means and to clear said passages in all positions of said block so as to permit combustiblE gases to pass into said passages from said crankcase unobstructed by said second positioning means.
 2. A combination in accordance with claim 1 and characterized further in that: a. there are two sets of passages in the wall of said block, said sets being spaced apart on opposite sides of said exhaust port; and b. said first positioning means is comprised of two symmetrical arcuate portions facing each other from between said sets of passages, both said portions being notched substantially at their centers to provide clearance for a crank rotating within said crankcase when the said block is in two of its alternative positions.
 3. In a two-cycle gasoline engine the combination comprising: a. a crankcase having an intake port for receiving a combustible mixture and a circular opening surrounded by a flange; b. a cylinder block having walls defining a cylindrical chamber open at one end to admit a piston and having a flange surrounding said open end, said cylinder also having an exhaust port through its side and a plurality of circumferentially spaced apart grooves running axially along its side wall from said flange toward the opposite end of said cylinder, said grooves being recessed in said side wall to a common depth defined by a circle concentric with said cylinder and substantially of the same size as the circular opening in said crankcase flange; c. a pair of arcuate positioning lips extending from the open end of said cylinder between said grooves; d. means for mounting said cylinder block upon said crankcase in any of several alternative positions in each of which said mounting flanges are juxtaposed and said positioning lips extend into the opening in said crankcase flange; and e. a set of centering bosses extending radially inwardly from the walls of said crankcase opening toward said positioning lips, said bosses being so distributed that all of them register with said positioning lips and none of them extend opposite one of said grooves regardless of the alternative position in which said cylinder block is mounted upon said crankcase, whereby said combustible mixture can flow unobstructed from said crankcase and through said grooves to the said opposite end of said cylinder regardless of the particular position in which said cylinder block is mounted.
 4. In a two-cycle gasoline engine the combination comprising: a. a crankcase having an opening and an intake port in its side; b. a carburetor mounted upon said crankcase at said intake port; c. a block having walls defining a cylinder with an exhaust port through its side; d. means for mounting said block upon said crankcase at said opening in alternative positions about the axis of said cylinder, thereby to permit different orientations of said exhaust port relative to said carburetor; e. a piston within the cylinder defining a combustion chamber with the end of the cylinder remote from the crankcase; f. means defining passages in the wall of said block open to said cylinder and open to the interior of the crankcase for permitting the combustible mixture to flow into the combustion chamber; and g. means on said block and said crankcase for laterally positioning the cylinder with respect to said crankcase opening, said positioning means being arranged to clear the passages in all positions of the block so as to permit the combustible mixture to pass through the passages from the crankcase unobstructed by the positioning means. 